What is it called when base units are combined, such as g/mL for density?

Correct Answer: B

Rationale: The correct answer is B: derived units. When base units (such as grams or milliliters) are combined, as seen in g/mL (grams per milliliter) for density, they form derived units. Derived units measure complex quantities that are derived from combinations of base units. Choice A, 'combined units,' is incorrect as it does not specifically refer to the formation of new units from base units. Choice C, 'base units,' is incorrect because base units are the fundamental units from which all other units are derived, not the combinations of units. Choice D, 'calculated units,' is incorrect as it does not accurately describe the concept of combining base units to form a new unit like g/mL for density.

Correct Answer: B

Rationale: The correct answer is B: 1000 grams. This is because by definition, 1 kilogram is equal to 1000 grams. Choice A, 100 grams, is incorrect as it underestimates the actual conversion. Choice C, 500 grams, and Choice D, 2000 grams, are also incorrect as they do not align with the correct conversion factor of 1 kilogram to 1000 grams.

Correct Answer: B

Rationale: The correct answer is B: derived units. When base units (such as grams or milliliters) are combined, as seen in g/mL (grams per milliliter) for density, they form derived units. Derived units measure complex quantities that are derived from combinations of base units. Choice A, 'combined units,' is incorrect as it does not specifically refer to the formation of new units from base units. Choice C, 'base units,' is incorrect because base units are the fundamental units from which all other units are derived, not the combinations of units. Choice D, 'calculated units,' is incorrect as it does not accurately describe the concept of combining base units to form a new unit like g/mL for density.

Correct Answer: A

Rationale: To convert 0.004 to a ratio, we first express it as 4/1000, which simplifies to 1/250. Hence, 0.004 is equivalent to the simplified ratio of 1:250. Choice B, 4:35, is incorrect as it does not reflect the correct conversion. Choice C, 7:28, is incorrect because it does not represent the simplified ratio of 0.004. Choice D, 4:00, is incorrect as it does not simplify to the original decimal value.

Correct Answer: B

Rationale: To convert liters to milliliters, you need to multiply by 1,000 since there are 1,000 milliliters in a liter. Therefore, 1.5 liters x 1,000 = 1,500 milliliters. Choice A, 15 mL, is incorrect as it represents the conversion of 0.015 liters. Choice C, 150 mL, is incorrect as it represents the conversion of 0.15 liters. Choice D, 150,000 mL, is incorrect as it represents the conversion of 150 liters.

Correct Answer: B

Rationale: To convert grams to milligrams, you need to multiply by 1,000 since there are 1,000 milligrams in a gram. Therefore, 3,450 grams 1,000 = 3,450,000 milligrams. Choice A (34,500 mg) is incorrect because it represents the result for converting grams to milligrams by a factor of 10 (not 1,000). Choice C (3,450 mg) is incorrect as it represents the original amount in grams, not the converted amount to milligrams. Choice D (3,450,000 mg) is incorrect as it is the same as the correct answer but with the comma in the wrong place, which would imply converting kilograms to milligrams rather than grams to milligrams.

Correct Answer: A

Rationale: In the metric system, 'km' stands for kilometer, which is a unit of length equal to 1,000 meters. This choice is correct as 'kilometer' is the standard unit for measuring long distances. Choice B, 'kilomole,' is incorrect as it is a unit in chemistry representing a quantity of substance. Choice C, 'kilobyte,' is incorrect as it is a unit of digital information storage, not a unit of measurement. Choice D, 'knot,' is incorrect as it is a unit of speed used in navigation and aeronautics, not a unit of length in the metric system.

Correct Answer: B

Rationale: 0.3 milliliters is equivalent to 0.3 ml. This is a precise measurement commonly used in medical settings for administering small doses of liquid medication. It is important to understand and recognize the decimal point placement when converting between milliliters and other volume units. Choice A (0.03 ml) is incorrect as it represents a smaller amount than 0.3 ml. Choice C (3 ml) and Choice D (30 ml) are also incorrect as they are larger measurements and do not match the given amount of 0.3 ml.

Correct Answer: B

Rationale: The correct formula to convert Fahrenheit to Celsius is C = (F - 32) 5/9. This formula is derived from the relationship between the two temperature scales. The incorrect choices can be ruled out as follows: A. F = (C 9/5) + 32 - This formula is used to convert Celsius to Fahrenheit. C. C = (F - 32) 9/5 - This formula incorrectly multiplies by 9/5 instead of dividing. D. F = (C + 32) 5/9 - This formula does not subtract the constant 32 from the Fahrenheit value.